Electroencephalography headset and system for collecting biosignal data

ABSTRACT

One variation of a system for collecting biosignal data includes: a left junction; a right junction; a first band spanning the left and right junctions; a first band adjuster configured to adjust a length of the first band between the left and right junctions; a second band spanning the left and right junctions and radially offset from the first band about a lateral axis spanning the left and right junctions; a second band adjuster configured to adjust a length of the second band between the left and right junctions; a first electrode fixedly mounted to the first band and centered between the left and right junctions; a second electrode mounted to the first band offset from the first electrode and laterally-adjustable along the length of the first band; and a third electrode mounted to the second band and laterally-adjustable along the length of the second band.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Application is a continuation of U.S. patent application Ser. No.16/880,953 filed on 21 May 2020, which is a continuation of U.S. patentapplication Ser. No. 15/831,143 filed on 4 Dec. 2017, both of whichclaim the benefit of U.S. Provisional Application No. 62/429,546, filedon 2 Dec. 2016, and all of which are incorporated in their entirety forall purposes by this reference.

This application is related to U.S. patent application Ser. No.15/351,016, filed on 14 Nov. 2016, which is incorporated in its entiretyby this reference.

TECHNICAL FIELD

This invention relates generally to the field of electroencephalographyand more specifically to a new and useful electroencephalography headsetin the field of electroencephalography.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a flowchart representation of an electroencephalography (or“EEG”) headset;

FIG. 2 is a schematic representation of one variation of the EEGheadset;

FIG. 3 is a schematic representation of one variation of the EEGheadset;

FIG. 4 is a schematic representation of one variation of the EEGheadset;

FIG. 5 is a schematic representation of one variation of the EEGheadset;

FIG. 6 is a schematic representation of one variation of the EEGheadset;

FIG. 7 is a flowchart representation of one variation of the EEGheadset;

FIG. 8 is a schematic representation of one variation of the EEGheadset; and

FIG. 9 is a schematic representation of one variation of the EEGheadset.

DESCRIPTION OF THE EMBODIMENTS

The following description of embodiments of the invention is notintended to limit the invention to these embodiments but rather toenable a person skilled in the art to make and use this invention.Variations, configurations, implementations, example implementations,and examples described herein are optional and are not exclusive to thevariations, configurations, implementations, example implementations,and examples they describe. The invention described herein can includeany and all permutations of these variations, configurations,implementations, example implementations, and examples.

1. System

As shown in FIGS. 1-8, a system for collecting biosignal data includes:a left junction 110; a right junction 112; a first band 121 spanning theleft junction 110 and the right junction 112; a first band adjuster 131configured to adjust a first length of the first band 121 between theleft junction 110 and the right junction 112; a second band 122 spanningthe left junction 110 and the right junction 112 and radially offsetfrom the first band 121 about a lateral axis spanning the left junction110 and the right junction 112; a second band adjuster 132 configured toadjust a second length of the second band 122 between the left junction110 and the right junction 112; a first electrode 140 fixedly mounted tothe first band 121 and centered between the left junction 110 and theright junction 112; a second electrode 152 mounted to the first band 121between the first electrode 140 and the left junction 110 andlaterally-adjustable along the first length of the first band 121; and athird electrode 153 mounted to the second band 122 between the leftjunction 110 and the right junction 112 and laterally-adjustable alongthe second length of the second band 122.

One variation of the system shown in FIGS. 1 and 9 defines anelectroencephalography (or “EEG”) headset and includes: a junction; afirst band 121 coupled to the junction; a first band adjuster 131configured to adjust a first length of the first band 121 extending fromthe junction; a first length scale 137 arranged on the first band 121and configured to indicate a particular length value, along the lengthscale 137, corresponding to a current length setting of the first band121; a second band 122 coupled to the junction and radially offset fromthe first band 121 about a lateral axis of the junction; a second bandadjuster 132 configured to adjust a second length of the second band 122extending from the junction; a first electrode 140; a first electrodeadjuster 141 coupling the first electrode 140 to the first band 121 overa range of lateral positions along the first length of the first band121 and including a set of electrode position labels 147 indicatingdiscrete lateral positions of the first electrode 140 in the firstelectrode adjuster 141, each electrode position label, in the set ofelectrode position labels 147, indicating a target lateral position ofthe first electrode 140 in the first electrode adjuster 141 for aparticular length value, along the length scale 137, indicated by thefirst band 121 according to an electrode placement standard; and asecond electrode 152 mounted to the second band 122 offset from thejunction.

As shown in FIGS. 1 and 2, another variation of the EEG headset 100includes: a left junction 110; a right junction 112; a first band 121adjustably coupled to and spanning the left junction 110 and the rightjunction 112; a first set of electrodes arranged along the first band121; a second band 122 adjustably coupled to and spanning the leftjunction 110 and the right junction 112 and radially offset from thefirst band 121; a second set of electrodes arranged along the secondband 122, the second set of electrodes including a second electrode 152fixedly coupled to the second band 122 and centered between the leftjunction 110 and the right junction 112; a third band 123 adjustablycoupled to and spanning the left junction 110 and the right junction 112and radially offset from the second band 122; a third set of electrodesarranged along the third band 123, the third set of electrodes includinga third electrode 153 fixedly coupled to the third band 123 and centeredbetween the left junction 110 and the right junction 112; a fourth band124 adjustably coupled to and spanning the left junction 110 and theright junction 112 and radially offset from the third band 123; and afourth set of electrodes arranged along the fourth band 124, the fourthset of electrodes including a fourth electrode 154 fixedly coupled tothe fourth band 124 and centered between the left junction 110 and theright junction 112

As shown in FIGS. 2 and 3, yet another variation of the EEG headset 100includes: a left junction no configured for placement adjacent a leftear of a user; a right junction 112 configured for placement adjacent aright ear of a user; a band 121 spanning the left junction 110 and theright junction 112; a band adjuster 131 configured to modify aneffective length of the band 121 between the left junction 110 and theright junction 112; a first electrode 140 fixedly mounted to the band121 and centered between the left junction no and the right junction112; a second electrode 152; a second electrode 152 adjustor coupled tothe band 121 between the first electrode 140 and the left junction noand supporting the second electrode 152 along a linear adjustment range;a third electrode 153; and a third electrode 153 adjustor coupled to theband 121 between the first electrode 140 and the right junction 112 andsupporting the third electrode 153 along a linear adjustment range.

2. Applications

Generally, the EEG headset 100 defines a singular structure containing aset of integrated electrodes arranged across a set of adjustable bandsthat can be expanded and retracted to fit heads of various shapes andsizes. The set of adjustable bands are arranged in particularorientations and are configured to locate both fixed and adjustableelectrodes in specific locations according to the 10-20 system (or otherelectrode placement standard). The set of integrated electrodes in theEEG headset 100 includes both: fixed electrodes, such as arranged ateach junction and along the anteroposterior centerline of various bands;and adjustable electrodes that can be adjusted along a limitedadjustment range to re-center these electrodes following adjustment oftheir corresponding bands. In particular, the EEG headset 100 includesmechanisms supporting both a limited number of macro adjustments atvarious bands and a limited number of micro adjustments at adjustableelectrodes to realize electrode placement rules defined by the 10-20system (or other electrode placement standard) within a positionaltolerance of the 10-20 system.

During setup of the EEG headset 100 on a user in preparation for an EEGtest, an EEG test administrator can place the EEG headset 100 on theuser's head and adjust the effective length of each band via bandadjusters in order to achieve a sufficiently close fit between each bandand the user's scalp. Because certain electrodes within the EEG headset100 (e.g., electrodes at the F7, F3, F4, F8, C3, C4, T5, P3, P4, and T6positions, shown in FIGS. 3 and 6) may no longer be properly centeredbetween adjacent fixed electrodes, the EEG test administrator can thenadjust these electrodes locally via their electrode adjusters to bringthe complete set of electrodes back into alignment with the 10-20system, as shown in FIG. 7.

The junctions and bands within the EEG headset 100 can define semi-rigidstructures configured to accurately and repeatably locate electrodes ona user's head according to the 10-20 system (or other electrodeplacement standard). Furthermore, each electrode can be integrated intoand irremovable from the EEG headset 100 (except for electrode tips,which may be replaceable, as described below) such that sense signalsread from each electrode during an EEG test can be automaticallytagged—by the EEG headset 100 or connected computing device—with acorrect channel label based on predefined locations of each electrodewithin the EEG. In particular, the EEG headset 100 can include a set ofjunctions, bands, band adjusters, electrodes, and electrode adjustersthat cooperate to define a system that can be relatively quicklyreconfigured for a new user by an EEG test administrator (or by theuser, etc.) to accurately and repeatably realize the 10-20 system (orany other EEG system), thereby enabling the EEG headset 100 to collectquality and properly-labeled EEG data during an EEG test.

3. Junctions, Bands, and Band Adjusters

The EEG headset 100 includes: a left junction no; a right junction 112;a first band 121 including a first end coupled to the left junction 110,a second end coupled to the right junction 112, a first band adjuster131 configured to adjust a distance between the first end and the leftjunction 110 and between the second end and the right junction 112; anda second band 122 radially offset from the first band 121 and includinga third end coupled to the left junction no, a fourth end coupled to theright junction 112, and a second band adjuster 132 configured to adjusta distance between the third end and the left junction no and betweenthe fourth end and the right junction 112. Generally, the left and rightjunctions no, 112 function to radially locate each band (e.g., thefirst, second, third, fourth, and fifth bands) in the EEG headset 100,and the bands function to support fixed and adjustable electrodesagainst a user's scalp according to electrode placement definitions andtolerance defined by the 10-20 EEG electrode configuration (or other EEGelectrode placement standard).

3.1 Junctions

The left and right junctions no, 112 can rest on a user's head justabove and in front of the user's left and right ears, respectively, andcan locate: the first band 121 at a 0° position; the second band 122 ata 40° position; the third band 123 at an 80° position; the fourth band124 at a 125° position; and the fifth band 125 at the 170° position. Inthis implementation, when the EEG headset 100 is worn by a user, theleft and right junctions 110, 112 can thus radially locate these bandssuch that: the first band 121 extends across the user's forehead; thesecond band 122 passes over the user's frontal lobe; the third band 123passes over the user's primary motor and somatosensory cortexes near thecentral sulcus; the fourth band 124 passes over the user's parietallobe; and the fifth band 125 extends across the back of the user's skulladjacent the user's occipital lobe according to the 10-20 system.

For example, and as shown in FIG. 1, the left junction 110, the rightjunction 112, the first band 121, the first band adjuster 131, thesecond band 122, the second band adjuster 132, the first electrode 140,the second electrode 152, and the third electrode 153, etc. cancooperate to define an adjustable EEG headset configured to be worn on ahead of a user. The left junction no can be configured to fall adjacenta left ear of the user when the adjustable EEG headset is worn on thehead of the user; and the right junction 112 can be configured to falladjacent a right ear of the user when the adjustable EEG headset is wornon the head of the user. The third band 123 can extend approximatelyalong a coronal plane over the head of the user when the adjustable EEGheadset is worn on the head of the user; and the second band 122 canextend over the head of the user between the third band 123 and aforehead of the user when the adjustable EEG headset is worn on the headof the user.

3.2 Band Adjustment

In one implementation shown in FIGS. 1 and 2, a band 121 includes: aleft strap defining a left internal rack 127 (or “toothed strap”) andextending from the left junction 110; a right strap defining a rightinternal rack 128 and extending from the right junction 112; and asleeve 126 enclosing the left internal rack 127 and the right internalrack 128. In this implementation, the electrodes can be coupled to thesleeve 126; a band adjuster 131 for this band can include a geararranged on the sleeve 126, engaged to the left internal rack 127relative to the right internal rack 128, manually operable in a firstdirection to expand the first band 121, and manually operable in asecond direction to contract the first band 121.

For example, a first band 121 extending toward the front of the EEGheadset 100 (e.g., configured to fall along, contact, or otherwiseengage a user's forehead) can include: a left strap extending from theleft junction 110 toward the front of the EEG headset 10 o and defininga left rack gear 127; and the right strap extending from the rightjunction 112 toward the front of the EEG headset 100, vertically offsetfrom the left strap, curving toward and overlapping the left strap, anddefining a right rack gear 128 facing the left rack gear 127. In thisimplementation, the first band 121 also includes a sleeve 126 that spansthe left and right junctions 110, 112 and encases the left and rightrack gears 127, 128. In this example, a first band adjuster 131 caninclude: a knurled knob arranged over or extending outside of the sleeve126; and a pinion arranged inside the sleeve 126, interposed between andmating with the left and right rack gears 127, 128 and radially coupledto the knob. Thus, when the EEG test administrator rotates the knob in afirst direction, the pinion can drive the left and right rack gears 127,128 apart, thereby increasing the effective length of the first band121. Similarly, when an EEG test administrator rotates the knob in asecond direction, the pinion can drive the left and right rack gears127, 128 toward each other, thereby shortening the effective length ofthe first band 121. In particular, rotation of the band adjuster 131 canuniformly shift the first and second ends of the first band 121 awayfrom (or toward) the left and right junctions 110, 112, respectively.Furthermore, surfaces on the left and right straps extending from theleft and right junctions 110, 112 can also include demarcations—such asprinted, embossed, or debossed alphabetic or numerical symbols in theform of a scale—that are exposed as the first band 121 is expanded,thereby visually indicating the adjustment position of the first band121.

In this implementation, the first band 121 can also include a lengthscale 137 corresponding to discrete lengths (or discrete lengthsub-ranges) of the first band 121, wherein each length value along thelength scale 137 corresponds to a particular electrode position label—ina set of electrode position labels 147—on a linear rack that couples anadjustable electrode to the first band 121, as described below, as shownin FIG. 2. The first band 121 (and/or the first band adjuster 131) canthus indicate a particular length value—along this length scale 137—thatcorresponds to a current length setting of the first band 121 as atechnician or EEG test administrator adjusts the EEG headset 100 for theunique size and shape of a user's head. For example: the length scale137 can include discrete textual symbols highlighted in a range ofdiscrete colors arranged on the left internal rack 127; and the sleeve126 can indicate a particular textual symbol, in the first sequence ofdiscrete textual symbols, corresponding to a current length setting ofthe first band 121 by obscuring all textual symbols other than theparticular textual symbol corresponding to the current length of thefirst band 121 or by aligning a pointer to this particular textualsymbol. As described below, the technician or EEG test administrator canthen manually shift adjustable electrodes on the first band 121 tolateral positions labeled with the same textual symbol and/or colorvalue in order to locate these adjustable electrodes within a thresholdlocational tolerance of their target locations on the user'sscalp—relative to each other, relative to a fixed electrode on the firstband 121, and/or relative to electrodes on other bands in the EEGheadset 100, etc.—specified by a 10-20 EEG electrode configuration or(other electrode placement standard). The technician or EEG testadministrator can repeat this process for each other band and adjustableelectrode in the EEG headset 100 in order to configure the EEG headset100 for the user.

In the foregoing implementation, each other band in the EEG headset 100can similarly include a left strap 127, and right strap 128, a sleeve126, and a band adjuster 131 configured to expand and contract the band121 when manipulated by an EEG test administrator. These left straps canterminate at the left junction 110, and these right straps can terminateat the right junction 112. The left and right junctions 110, 112 cantherefore form reference locations on a user's head (e.g., above andimmediately ahead of the user's ears) and can radially locate the bands(e.g., the first, second, third, fourth, and fifth bands) relative toone another and relative to these reference locations such that—once thebands are adjusted to length and the adjustable electrodes positionedaccordingly—the set of sense electrodes within the EEG headset 100 fallwithin threshold distances of target electrode positions specified inthe 10-20 EEG electrode configuration (or other electrode placementstandard).

In another implementation shown in FIG. 9, the EEG headset 100 includes:a central body configured for placement on the top of a user's headalong the anteroposterior centerline of the user's skull; a set ofadjustable bands extending downwardly from the central body; and a setof fixed electrodes and adjustable electrodes distributed across theinterior surfaces of the bands and the central body. In thisimplementation, each band can be independently adjustable and caninclude at least one electrode (e.g., one fixed electrode or one fixedelectrode and one adjustable electrode). Alternatively, pairs of likeleft and right bands can be linked by a common band adjuster such thatpairs of like bands are uniformly adjusted relative to the centerline ofthe central body.

In the foregoing implementations, the left junction 110, right junction112, bands, and band adjusters, etc. can be formed in a rigid material,such as injection-molded plastic (e.g., nylon) or moldedfiber-impregnated polymer. However, the junctions, bands, and/or centralbody, etc. can be formed in any other material or define any othergeometry.

3.3 Chin Strap

In one variation, the EEG headset 100 further includes a chin strapcoupled to the left and right junctions (or to one or more bands) andconfigured to fix the EEG headset 100 to a user's chin, ears, or otherhead feature, thereby preventing the EEG headset 100 moving relative tothe user's head and from falling off of the user's head if the usermoves during an EEG test performed with the EEG headset 100.

4. Sense Electrodes

The EEG headset 100 includes a set of sense electrodes arranged acrossthe set of bands. When the EEG headset 100 is worn by the user, a senseelectrode can: contact the user's scalp; detect a high-impedance sensesignal from the user's skin; convert the low-amplitude, high-impedancesense signal into a well-driven low-impedance sense signal; and pass thelow-impedance sense signal to the controller 184.

4.1 Electrode Composition

Each sense electrode is configured to contact a user's skin and to passneural oscillation data in the form of a sense signal from the user'sskin to the controller 184 (e.g., to a signal processor within thecontroller 184). For example, each sense electrode in the set of senseelectrodes can define a dry EEG electrode including: a substrate; a setof electrically-conductive prongs extending from a first side of thesubstrate; and an amplifier coupled to the substrate opposite the set ofprongs and configured to amplify an electrical signal passing throughthe set of prongs. The electrically-conductive prongs can be elastic(e.g., gold-plated silicone bristles) or rigid (e.g., gold-plated copperprongs). A sense electrode can alternatively include a flat or domedcontact disk configured to contact the user's skin.

As shown in FIG. 4, the sense electrode can also be configured to acceptinterchangeable electrode tips 144, such as one of an elastic bristleelectrode tip, a rigid prong electrode tip, a flat contact diskelectrode tip, and a domed contact disk electrode tip, as describedbelow. In one implementation, each sense electrode can include: anelectrode body 142 coupled to the band 121 (e.g., via an electrodeadjuster 141, such as in the form of a linear rack, for adjustableelectrodes); a magnetic element 143 arranged on a distal end of theelectrode body 142 and including a conductive surface; and a conductivelead 146 coupled to a face of the magnetic element 143, passing throughthe electrode body 142, and terminating at an amplifier electricallycoupled to the controller 184, such as arranged in the control module180 described below. In this implementation, the EEG headset 100 can besupplied with a kit of electrode tips 144, wherein each electrode tip inthe kit of electrode tips 144 includes a ferrous element 148 configuredto transiently magnetically couple to the magnetic element 143 and totransiently electrically couple to the conductive lead 146 via theconductive surface of the magnetic element 143. In this implementation,a hard or soft contact surface on an electrode tip can electricallycouple to the ferrous element 148 on the back side of the electrode tip;the magnetic element 143 can include an electrically-conductive surface(e.g., chrome or tin plating); and the amplifier—such as arranged insidethe electrode body 142 or nearby in the adjacent band—can electricallycouple to the magnetic element 143 via a wire arranged inside of theelectrode body 142. When an electrode tip is thus installed on anelectrode, the ferrous element 148 in the electrode tip can directlycontact the magnetic element 143, thereby electrically coupling thecontact surface of the electrode tip 144 to the amplifier. For example,a first end of the conductive lead 146 can be bonded to (e.g., pottedaround) a face of the magnetic element 143 with (conductive) adhesive,compressed against the face of the magnetic element 143 with a springarranged inside the electrode body 142, or connected to a spring loadedpin in contact with the face of the magnetic element 143. A separateconductive lead 146 connected to an output of the amplifier can passthrough the band 121 and connect to an input of the controller 184.

In the foregoing implementation, the kit of electrode tips 144 caninclude electrode tips 144 defining different constant surfaces, such asone each of a hard domed electrode surface, a hard pronged electrodesurface, and a soft domed electrode surface. Electrodes in the kit canalso define various lengths, such as matched to lengths of supportblocks installed on adjacent regions of a band 121, as described belowand shown in FIG. 4, such as to enable an EEG test administrator toreconfigure the EEG headset 100 for both adult and juvenile users.

4.2 Adjustable and Fixed Electrode Layout

As shown in FIGS. 3 and 4, the EEG headset 100 can include electrodesmounted to the interior surfaces of corresponding bands via electrodeadjusters (hereinafter “adjustable electrodes”) at select locations(e.g., at other than the lateral centerline of the EEG headset 100, theimmediate front and rear of the EEG headset 100, and the lateral extentsof the EEG headset 100). The EEG headset 100 can also include electrodesfixedly coupled to the interior surfaces of corresponding bands(hereinafter “fixed electrodes”) at other locations.

In one implementation: the EEG headset 100 includes nineteen senseelectrodes in a combination of fixed and adjustable configurationsarranged across the set of bands, including one sense electrode for eachof: the F7, Fp1, Fp2, and F8 positions (defined in the 10-20 system)along the first band 121; the F3, Fz, and F4 positions along the secondband 122; the T4 position at the right junction 112; the T3 position atthe left junction 110; the C3, Cz, and C4 positions along the third band123; the P3, Pz, and P4 positions along the fourth band 124; and the T5,O1, O2, and T6 positions along the fifth band 125, as shown in FIGS. 3and 6. In particular, in this example: the first band 121 can includefixed sense electrodes at the Fp1 and Fp2 sense electrode positions andadjustable sense electrodes at the F7 and F8 sense electrode positions;the second band 122 can include a fixed sense electrode at the Fz senseelectrode position and adjustable sense electrodes at the F3 and F4sense electrode positions; the third band 123 can include a fixed senseelectrode at the Cz sense electrode position and adjustable senseelectrodes at the C3 and C4 sense electrode positions; the fourth band124 can include a fixed sense electrode at the Pz sense electrodeposition and adjustable sense electrodes at the P3 and P4 senseelectrode positions; and the fifth band 125 can include fixed senseelectrodes at the T5 and T6 sense electrode positions and adjustable (orfixed) sense electrodes at the O1 and O2 sense electrode positions. TheEEG headset 100 can also include fixed sense electrodes at the T4 senseelectrode position at the right junction 112 and at the T3 senseelectrode position at the left junction 110, as shown in FIG. 6. The EEGheadset 100 can further include a fixed drive electrode fixedly mountedto the first band 121 between the FP1 and FP2 sensor electrodepositions, centered between the left junction 110 and the right junction112, and configured to contact a user's skin proximal the user'sforehead (e.g., centered just above the bridge of the user's nose).

In particular, in addition to the first band 121 and the second band122, the EEG headset 100 can include: a third band 123 spanning the leftjunction 110 and the right junction 112 and supporting alaterally-adjustable C3 electrode, a fixed Cz electrode, and alaterally-adjustable C4 electrode in the 10-20 EEG electrodeconfiguration; a third band adjuster 133 configured to adjust a lengthof the third band 123 between the left junction 110 and the rightjunction 112; a fourth band 124 spanning the left junction 110 and theright junction 112 and supporting a laterally-adjustable P3 electrode, afixed Pz electrode, and a laterally-adjustable P4 electrode in the 10-20EEG electrode configuration; a fourth band adjuster 134 configured toadjust a length of the fourth band 124 between the left junction 110 andthe right junction 112; and a fifth band 125 spanning the left junction110 and the right junction 112 and supporting a laterally-adjustable T5electrode, a fixed O1 electrode, a fixed O2 electrode, and alaterally-adjustable T6 electrode in the 10-20 EEG electrodeconfiguration, as shown in FIGS. 1, 3, and 6.

Therefore, in the foregoing example: a first electrode 140 mounted tothe first band 121 can define a laterally-adjustable F7 electrode; asecond electrode 152 mounted to the first band 121 between the firstelectrode 140 and the right junction 112 can be laterally-adjustablealong the first length of the first band 121 to define alaterally-adjustable F8 electrode; a third electrode 153 fixedly mountedto the first band 121 between the first electrode 140 and the secondelectrode 152 can define a fixed FP1 electrode; a fourth electrode 154fixedly mounted to the first band 121 between the second electrode 152and the third electrode 153 can define a fixed FP2 electrode; a fifthelectrode 155 fixedly mounted to the first band 121 between the thirdelectrode 153 and the fourth electrode 154 (e.g., centered between theleft junction 110 and the right junction 112) can define a fixed driveelectrode; a sixth electrode 156 mounted at the lateral centerline ofthe second band 122 can define a fixed Fz electrode; a seventh electrode157 mounted to the second band 122 between the sixth electrode 156 andthe left junction 110 can define a laterally-adjustable F3 electrode;and an eighth electrode 158 mounted to the second band 122 between thesixth electrode 156 and the right junction 112 can belaterally-adjustable along the second length of the second band 122 todefine a laterally-adjustable F4 electrode in the 10-20 EEG electrodeconfiguration; etc.

Furthermore, each band adjuster can be configured to expand itscorresponding band equally between the left junction 110 and the rightjunction 112 in order to maintain certain fixed electrodes along thelateral centerline of the EEG headset 100. For example, the second band122 can include a fixed electrode in the Fz position, and the secondband adjuster 132 can be configured to expand the second band 122equally between the left junction 110 and the right junction 112 inorder to maintain the Fz electrode along the lateral centerline of theEEG headset 100. Similarly, the third band 123 can include a fixedelectrode in the Cz position, and the third band adjuster 133 can beconfigured to expand the third band 123 equally between the leftjunction 110 and the right junction 112 in order to maintain the Czelectrode along the lateral centerline of the EEG headset 100.

4.2 Adjustable Electrode

In one implementation shown in FIGS. 4, 5, and 8, an adjustableelectrode includes: a sense electrode; a sliding element supporting thesense electrode; a ratchet mechanism (or rack gear and follower) mountedto a band 121 and configured to retain the position of the slidingelement relative to the band 121; and a button that, when manuallydepressed, releases the sliding element from the ratchet mechanism (orreleases the follower from the rack gear), thereby enabling an EEGadministrator to shift the position of the sliding element—and thereforethe sense electrode—relative to the band 121. In this implementation,the sliding element and ratchet mechanism can cooperate to locate thesense electrode across a range of positions, including a linear distanceparallel to the length of its corresponding band and equal toapproximately half of the maximum change in effective length of the band121 from its fully-retracted to fully-expanded positions such that theadjustable electrode can be centered between two adjacent fixedelectrodes according to the 10-20 system substantially regardless ofadjustment positions of the band 121. Furthermore, the band 121supporting the adjustable electrode can include demarcations—such asprinted, embossed, or debossed alphabetic or numerical symbols in theform of a scale—adjacent the button to visually indicate the adjustmentposition of the adjustable electrode, as shown in FIG. 5.

In a similar implementation shown in FIG. 5, an adjustable electrodeincludes: a sense electrode; and an electrode adjuster 141 coupling thesense electrode to a corresponding band over a range of lateralpositions along the length of the band 121. For example, the electrodeadjuster 141 can include a linear rack, and the sense electrode can bemounted to the linear rack via a ratchet or detent mechanism thatselectively retains the sense electrode in discrete locations along thelinear rack. The electrode adjuster 141 can also include a set ofelectrode position labels 147 (e.g., a lateral position scale)indicating discrete lateral positions of the sense electrode along theelectrode adjuster 141, wherein each electrode position label—in thisset of electrode position labels 147—indicates a target lateral positionof the sense electrode along the electrode adjuster 141 for a particularlength value—along the length scale 137—indicated by the band 121, asdescribed above, according to an electrode placement standard (e.g., a10-20 EEG electrode configuration). In particular, the band 121 caninclude a length scale 137 corresponding to discrete lengths of the band121, wherein each length value along the length scale 137 indicatescorrespondence to a particular electrode position label in the set ofelectrode position labels 147 on the linear rack. As described above,the band 121 can indicate a particular length value—along the lengthscale 137—corresponding to a current length setting of the band 121, andan EEG test administrator can adjust the sense electrode along thelinear rack to match the electrode position label indicated by the senseelectrode to the particular length value indicated by the band 121 inorder to locate the sense electrode within a threshold tolerance of itstarget position relative to another sense electrode in the EEG headset100.

For example, the length scale 137 on the band 121 can include a firstsequence of discrete textual symbols highlighted in a range of discretecolors arranged on the left internal rack 127, as shown in FIG. 2; theadjustable electrode can be assigned a target location relative toanother electrode (e.g., a fixed electrode arranged along the lateralcenterline of the EEG headset 100) on the band 121 according to a 10-20EEG electrode configuration; and the set of electrode position labels147 on the linear rack can include a second sequence of discrete textualsymbols highlighted in the range of discrete colors and arranged alongthe linear rack, as shown in FIG. 5, wherein each textual symbol in thesecond sequence of discrete textual symbols indicates a target lateralposition of the second electrode 152 along the linear rack for acorresponding textual symbol—in the first sequence of discrete textualsymbols—indicated by the band 121. Each adjustable band and each otheradjustable electrode on each adjustable band can be similarly annotatedwith length scales and electrode position labels 147, respectively, toassist an EEG test administrator in rapidly adjusting the EEG headset100 to a user's unique head geometry by: adjusting the bands to fit theuser's head; and then shifting each sense electrode in its linear rackto match its electrode position label to the length value of itscorresponding band.

4.4 Junction Electrodes

In one variation shown in FIGS. 1 and 3, the left junction 110 isconfigured for placement adjacent a left ear of the user, and the rightjunction 112 is laterally offset from the left junction 110 andconfigured for placement adjacent a right ear of the user when theadjustable EEG headset is worn on the head of the user. In thisvariation, a T3 electrode can be fixedly mounted to the left junction110, and a T4 electrode can be fixedly mounted to the right junction112.

Because the geometry of the left and right junctions 110, 112 and theuser's ears and hair near the left and right junctions 110, 112 mayvisually obstruct these T3 and T4 electrodes and thus inhibit an EEGtest administrator from easily observing contact between theseelectrodes and the user's scalp, the EEG headset 100 can also include: aleft light element 170 adjacent the T3 electrode, facing inwardly fromthe left junction 110 toward the right junction 112, and configured toilluminate the T3 electrode adjacent a scalp of the user when theadjustable EEG headset is worn on the head of the user; and a rightlight element 170 adjacent the T4 electrode, facing inwardly from theright junction 112 toward the left junction 110, and configured toilluminate the T4 electrode adjacent the scalp of the user when theadjustable EEG headset is worn on the head of the user, as shown in FIG.3. The EEG headset 100 (e.g., the controller 184) can therefore activatethe left and right light elements 170 during a setup period preceding anEEG test and/or throughout the EEG test in order to illuminate the T3and T4 electrodes, thereby better enabling the EEG test administrator toquickly visually observe these electrodes and make adjustments to theseelectrodes or to the band 121 to improve contact with the user's scalp.

4.5 Support Blocks

Each adjustable electrode (and each fixed electrode) can also include aspring element 149 between the sense electrode and the sliding elementand configured to depress the electrode toward a user's head and toabsorb variations in distances between the band 121 and users' scalpswhen the EEG headset 100 is worn by a variety of users.

In one implementation shown in FIGS. 2, 3, and 4, the EEG headset 100further includes support blocks: arranged on each side of electrodes onthe bands; configured to elevate the bands off of the scalp of the userand thus improve manual access to electrodes facing inwardly from thesebands; and to rest on the head of a user and thus distribute the weightof EEG headset 100 on the user's head, which may be more comfortable fora user than smaller electrodes (such as with pronged tips) carrying theweight of the EEG headset 100 into the user's scalp. For example, theEEG headset 100 can include: a first support block 161 arranged on thefirst band 121 between the first electrode 140 and the second electrode152, extending toward a median of a lateral axis coinciding with theleft junction 110 and the right junction 112, and defining a firstsurface facing the lateral axis and configured to rest against a head ofa user; and a second support block 162 arranged on the first band 121adjacent the second electrode 152 laterally opposite the first supportblock 161, extending toward the median of the lateral axis, and defininga second surface facing the lateral axis and configured to rest againstthe head of the user. In this example, the support blocks can includesolid or rigid hollow structures with soft (e.g., foam, rubber) surfacesconfigured to contact a user's head and to cushion the weight of the EEGheadset 100 on the user's head.

In this implementation, the second electrode 152 can include: anelectrode body 142 coupled to the first band 121; an electrode tip 144coupled to the electrode body 142 opposite the first band 121, asdescribed above; and a spring element 149 arranged inside the electrodebody 142 and configured to bias the electrode tip 144 past the firstsurface and the second surface toward the median of the lateral axis, asshown in FIG. 8. In particular, the electrode tip 144 of the secondelement can extend inwardly past the soft surfaces of the support blocksby a minimal distance (e.g., approximately three millimeters) at fullextension, and the spring element 149 can bias the second electrode 152to full extension. When the EEG headset 100 is placed on a user's head,the tip of the second electrode 152 can fall against the user's scalp,and the weight of the EEG headset 100 over the second electrode 152 cancompress the spring element 149 in the second electrode 152, therebycollapsing the second electrode 152 until the adjacent support blockscontact the user's scalp. The spring element 149 can thus compress theelectrode tip 144 of the second electrode 152 against the user's scalpwith substantially consistent force (e.g., within a narrow range oftarget electrode tip 144 forces or pressures); and the support blockscan carry (some of) the load of the EEG headset 100 into the user'shead. Because the soft surfaces of the support blocks define largersurface areas than the second electrode 152, the support blocks can thusdecrease local pressures of the EEG headset 100 on the user's scalp andyield improved comfort for the user.

In this implementation, the second electrode 152 can also include ashoulder 145 adjacent the electrode tip 144, such as defining a rimextending radially about the electrode body 142 aft of and coupled tothe electrode tip 144, as shown in FIGS. 5 and 8. The spring element 149can further support manual retraction of the electrode tip 144—via theshoulder 145—past the surfaces of the adjacent support blocks toward thefirst band 121 in order to separate the electrode tip 144 from the headof the user during lateral adjustment of the first electrode 140 on thefirst band 121. In particular, rather than maintaining contact betweenthe electrode tip 144 of the second electrode 152 and the user's scalpwhile moving the second electrode 152 laterally along its electrodeadjuster 141, while may be uncomfortable for the user and cause theelectrode tip 144 to separate from the electrode body 142, an EEG testadministrator may: grip the shoulder 145 between her thumb andforefinger (with the base of the thumb adjacent the first band 121);retract the second electrode 152 toward the first band 121 to separatethe electrode tip 144 from the user's scalp; draw the second electrode152 laterally to a target position—indicated by electrode positionlabels 147—on the electrode adjuster 141; and then release the shoulder145. The spring element 149 can thus drive the electrode tip 144 forwardand back into contact with the user's scalp and retain the electrode tip144 in contact with the user's scalp within the target electrode tip 144force range.

As described above and shown in FIG. 4, the electrodes can includereplaceable electrode tips 144 of various geometries. The EEG headset100 can therefore also include a kit of support blocks of variousgeometries (e.g., lengths) matched to the geometries of variouselectrode tips 144. For example, the electrode tip 144 of the secondelectrode 152 can be transiently coupled to the electrode body 142 ofthe second electrode 152 and can be configured for installation on theelectrode body 142 in combination with installation of the first supportblock 161 and the second support block 162 on the first band 121 suchthat this electrode tip 144 extends inwardly just past the innersurfaces of the first and second support blocks 161, 162 when the secondelectrode 152 is at full extension with this electrode tip 144installed. In this example, the EEG headset 100 can also include: athird support block defining a height greater than the height of thefirst support block 161 and interchangeable with the first support block161 on the first band 121; a fourth support block 164 defining a heightgreater than the height of the second support block 162 andinterchangeable with the second support block 162 on the first band 121;and including a second electrode 152 tip configured to transientlycouple to the electrode body 142 of the second electrode 152,interchangeable with the electrode tip 144 on the electrode body 142 ofthe second electrode 152; defining a length greater than the electrodetip 144; and configured for installation on the electrode body 142 incombination with installation of the third support block and the fourthsupport block 164 on the first band 121. In particular, the heights ofthe third and fourth support blocks 163, 164 can be matched to thelength of the second electrode 152 tip such that the longer secondelectrode 152 tip extends inwardly just past the inner surfaces of thethird and fourth support blocks when the second electrode 152 is at fullextension with the second electrode 152 tip installed. In this example,the support blocks can be snapped, fastened, or otherwise transientlyconnected to support block receptacles between electrodes on the bands.

Other electrodes on the EEG headset 100 can include similar springelements 149 and shoulders 145, and the EEG headset 100 can includesimilar support blocks mounted to the ends adjacent these otherelectrodes. However, the EEG headset 100 can include any other type andgeometry of electrode tips 144 and matched support blocks of any othermaterial or geometry.

Furthermore, the adjustable electrode can include a slotted grommetarranged between the sliding element and the sense electrode. Forexample, the slotted grommet can be of a compressible material (e.g.,silicone foam), configured to prevent ingress of debris into the ratchetmechanism, and configured to damp motion of the sense electrode relativeto the band 121 and to retain the position of the sense electroderelative to the band 121 in order to reduce noise in a sense signal readfrom the sense electrode during an EEG test. Each adjustable electrode(and each fixed electrode) can additionally or alternatively include ascrew element that, when adjusted by an EEG test administrator, drivesthe entire sense electrode (or the electrode tip 144 of the senseelectrode exclusively) toward or away from the band 121, therebyenabling the EEG test administrator to tune a force applied by anelectrode tip 144 to an adjacent surface of the users skin and toconfigure the EEG headset 100 for users having heads of different shapesand geometries.

However, an adjustable electrode within the EEG headset 100 can be ofany other form and can be configured in any other way to locate a senseelectrode across a variety of users' heads—of different shapes andsizes—according to the 10-20 EEG electrode configuration (or other EEGelectrode placement standard). The EEG headset 100 can also include anyother number and type of active or passive, dry or wet sense electrodesconfigured to output any other low- or high-impedance signal to a signalprocessor or controller 184 in the EEG headset 100, as described below.

4.6 Electrode Position Feedback

In this variation, the EEG headset 100 (and/or the native EEG testapplication executing on an external computing device) can detect globaladjustments of the EEG headset 100 at each band and local adjustments ateach adjustable electrode to confirm that the position of eachadjustable electrode conforms to the 10-20 system, such as within apredefined tolerance (e.g., +/− five millimeters). The EEG headset 100(or native EEG test application hosting an EEG portal on an externalcomputing device connected to the EEG headset 100) can serve prompts toan EEG test administrator—in real-time—to adjust certain adjustableelectrodes in order to bring the EEG headset 100 into alignment with the10-20 system prior to start of an EEG test.

In one implementation, the first band 121 includes a band 121potentiometer interposed between the first band 121 and the left (orright) junction, wherein the internal electrical resistance of the band121 potentiometer changes as a function of an adjusted position of thefirst band 121, such as a function of a distance between a first end ofthe first band 121 and the left junction 110. In this implementation,the EEG headset 100 also includes: an F4 electrode adjuster supportingan F4 sense electrode proximal an F7 position on the first band 121; anF8 electrode adjuster supporting an F8 sense electrode proximal an F8position on the first band 121; an F7 electrode potentiometer coupled tothe first band 121 and to the F7 electrode adjuster and exhibiting achange in internal resistance as a function of the position of the F7electrode adjuster on the first band 121; and an F8 electrodepotentiometer coupled to the first band 121 and to the F8 electrodeadjuster and exhibiting a change in internal resistance as a function ofthe position of the F8 electrode adjuster on the first band 121.

During setup, the controller 184 can sample the band 121, F7 electrode,and F8 electrode potentiometers and then implement methods andtechniques described below to calculate: a length of the first band 121based on a voltage (or internal resistance) read from the band 121potentiometer; a position of the F7 electrode relative to the first band121 based on a voltage (or internal resistance) read from the F7electrode potentiometer; and a position of the F8 electrode relative tothe first band 121 based on a voltage (or internal resistance) read fromthe F8 electrode potentiometer, such as based on a lookup table or setof parametric equations for each of these potentiometers. The controller184 can then calculate a target position of the F7 electrode based onthe length of the first band 121, such as a singular target position(e.g., in the form of a target voltage or resistance of the firstelectrode 140 potentiometer) or a target voltage range (e.g., in theform of a target voltage or resistance range of the first electrode 140potentiometer) based on predefined rules of the 10-20 system. Thecontroller 184 can implement similar methods and techniques to calculatea target position of the F8 electrode. The controller 184 can thencompare the actual positions of the F7 and F8 electrodes to the targetpositions or target position ranges of the F7 and F8 electrodes toconfirm that the F7 and F8 electrodes fulfill rules defined by the 10-20system.

Alternatively, the controller 184 can: access a lookup table that linksa voltage (or resistance) read from the band 121 potentiometer on thefirst band 121 directly to a singular target potentiometer voltage foreach of the F7 and F8 electrode potentiometers; calculate a differencebetween the singular target potentiometer voltages and actual voltagesread from the F7 and F8 potentiometers; and then directly confirmalignment of the F7 and F8 electrode to the 10-20 system if thesedifferences do not exceed a threshold voltage difference representing atolerance of the 10-20 system.

If the controller 184 confirms that one or both of the F7 and F8electrodes are positioned outside of an acceptable range of positions onthe first band 121 necessary to realize the 10-20 system, the controller184 can transmit a notification to correct the position of the F7 and/orF8 electrodes to an external computing device connected to the EEGheadset 100, such as to a computing device executing a native EEG testapplication hosting the EEG portal. For example, for the EEG headset 100that includes symbolic position indicators adjacent each adjustableelectrode, as described above, the EEG headset 100 can transmit to theconnected computing device a notification to correct the position of theF7 electrode, including a target positional character (e.g., “5/10” or“E”) at which to set the F7 electrode adjustor if the F7 electrode isdetermined to be outside of its acceptable positional range. In anotherexample, the EEG headset 100 can transmit to the computing device anotification specifying an approximate physical distance and directionto shift the F7 electrode in order to realize the 10-20 system. In theseexamples, upon receipt of such a notification from the EEG headset 100,the native EEG test application can render this notification on adisplay of the computing device. The native EEG test application canadditionally or alternatively update a virtual representation of the EEGheadset 100 rendered on the computing device to indicate that the F7electrode requires adjustment, such as by highlighting the F7 electrodein a virtual representation of the EEG headset 100 and inserting adirectional arrow and target offset distance to shift the F7 electrodeinto alignment with the 10-20 system.

The EEG headset 100 can additionally or alternatively include lightelements 170 (e.g., LEDs) arranged on the bands adjacent each adjustableelectrode, and the controller 184 can update the state of each lightelement 170 to visually indicate directly on the EEG headset 100 whichadjustable electrodes require repositioning to realize the 10-20 system.For example, the EEG headset 100 can include a first multicolor LEDarranged on the first band 121 adjacent one end of the adjustment rangeof the F7 electrode and a second multicolor LED arranged on the firstband 121 adjacent the opposite end of the adjustment range of the F7electrode. The EEG headset 100 can then update the state of one of thesemulticolor LEDs to output a flashing “red” light to visually indicate aneed to move the F7 electrode away from this LED and toward the opposingLED. Once the F7 electrode is correctly repositioned, the EEG headset100 can update the first and second multicolor LEDs to output “green”light to visually indicate that the F7 electrode is properly positioned.Similarly, the EEG headset 100 can include a multicolor LED adjacenteach adjustable electrode, and the EEG headset 100 can trigger each LED:to output a “red” color if the position of the adjacent electrodediffers significantly from a target electrode position; to output a“yellow” color if the position of the adjacent electrode is just outsideacceptable bounds of a target electrode position; and to output a“green” color if the position of the adjacent electrode is withinacceptable bounds of a target electrode position.

The system can include similar arrangements of electrode potentiometersat other adjustable electrodes in the EEG headset 100, and the EEGheadset 100 (and/or the native EEG test application executing on theconnected computing device) can implement similar methods and techniquesto confirm that the position of each adjustable electrode fulfills the10-20 system. During setup, the EEG headset 100 can regularly samplethese potentiometers to track the position of each adjustable electrodeand provide feedback to the EEG test administrator in (near) real-timedirectly through the EEG headset 100 or through an EEG portal at theconnected computing device until the EEG headset 100 is properlyconfigured according to the 10-20 system (or other electrode placementstandard). Furthermore, the EEG headset 100 (and/or the native EEG testapplication) can reject a request to start an EEG test at the EEGheadset 100 until all electrodes in the EEG headset 100 are confirmed intheir proper positions according to the 10-20 system. (Similarly, theEEG headset 100 and/or the native EEG test application can reject arequest to start an EEG test at the EEG headset 100 until all electrodesspecified as active in the upcoming EEG test or at least a thresholdnumber of electrodes specified in the upcoming EEG headset are confirmedin their proper positions according to the 10-20 system, such as withina tolerance of three millimeters or 5%. The EEG headset 100 (and/or thenative EEG test application) can implement similar methods andtechniques throughout the subsequent EEG test performed at the EEGheadset 100 to confirm that adjustable electrodes within the band 121remain in proper position on the user's head and to provide relatednotifications to the EEG test administrator in (near) real-time untilthe EEG test is complete.

However, each adjustable electrode and each band in the EEG headset 100can include any other type of positional sensor arranged in any otherway in the EEG headset 100 and configured to output a signalrepresentative of the relative position of its corresponding electrodeand the length of each band in the EEG headset 100. For example, ratherthan a linear potentiometer, each band can include a mechanical,optical, or magnetic optical encoder, such as in linear or rotationalformat.

4.7 Sense Electrode Contact Force

In this variation (and other variations described below), the EEGheadset 100 can also include a pressure sensor interposed between eachsense electrode and its corresponding band. For example, for each senseelectrode, the EEG headset can include a conductive foam,diaphragm-type, or piezoelectric pressure sensor configured to output asignal representative of a force applied by the sense electrode to theuser's skin. The EEG headset can thus sample each pressure sensor toconfirm that each sense electrode is applying at least a minimum force(or pressure) to the user's skin, that each sense electrode is applyingbetween a threshold minimum force and a threshold maximum force to theuser's skin, and/or that all sense electrodes in the EEG headset areapplying substantially similar forces (or pressures) to the user's skin.The EEG headset (or the native EEG test application executing on theconnected computing device) can then serve prompts to the EEG testadministrator to confirm that each sense electrode is properly depressedonto the user's skin and/or to prompt the EEG test administrator totighten or loosen select electrodes in order to achieve these appliedforce targets before beginning the EEG test.

4.8 Contact Loss Feedback

The EEG headset 100 can additionally or alternatively include lightelements 170 facing outwardly from the bands adjacent correspondingelectrodes, and the controller 184 can selectively activate these lightelements 170 during an EEG test in order to visually indicate to an EEGtest administrator when an electrode has lost contact with the user'sskin. For example, the EEG headset 100 can include a first light element170 arranged on the first band 121 adjacent the first electrode 140 andfacing outwardly from the first band 121; and the controller 184 canread a signal from the first electrode 140, characterize contact qualitybetween the first electrode 140 and a scalp of a user (e.g., based onfeatures in this signal or based on an output of a pressure sensorcoupled to the first electrode 140), and selectively activate the firstlight element 170 in response to detecting improper contact between thefirst electrode 140 and the scalp of the user, as described in U.S.patent application Ser. No. 15/351,016.

5. Fixed Sense Electrodes

In one variation, rather than a single discrete electrode at eachadjustable electrode position described below, the EEG headset includesa linear array of multiple discrete electrodes (hereinafter an“electrode array”) fixedly coupled to a band 121, and the EEG headset100 (e.g., the controller 184) or external computing device connected tothe EEG headset 100 selectively activates one electrode in eachelectrode array that best realizes electrode placement rules of the10-20 EEG electrode configuration (or other EEG electrode placementstandard). For example, the EEG headset 100 includes one electrode arrayat each of the: F7 and F8 electrode positions along the first band 121;the F3 and F4 electrode positions along the second band 122; the C3 andC4 electrode positions along the third band 123; the P3 and P4 electrodepositions along the fourth band 124; and the O1 and O2 electrodepositions along the fifth band 125.

In this variation, each electrode array can include a set of discretesense electrodes—as described above—packaged into a single block withthe center-to-center distances between adjacent electrodes equal to orless than an electrode positional tolerance defined by the 10-20 system.For example, for an electrode positional tolerance of +/− fivemillimeters, the center-to-center distance between adjacent senseelectrodes in one electrode array can be less than or equal to tenmillimeters such that a particular electrode in an electrode array mayfall within the positional tolerance of a target electrodepositional—according to the 10-20 system—and can then be activatedaccordingly, as described below. Furthermore, each sense electrode in anelectrode array can include: a discrete substrate; a discrete set ofelectrically-conductive prongs extending from a first side of thesubstrate; and a discrete amplifier coupled to the substrate oppositethe set of prongs and configured to amplify an electrical signal passingthrough the set of prongs. In particular, each electrode in an electrodearray can be electrically isolated from other electrodes in theelectrode array and can be selectively activated and deactivatedindependently of other electrodes in the same electrode array, such asby connecting and disconnecting the electrode from both power and groundterminals in the EEG headset 100.

5.1 Manual Activation

In one implementation, an EEG test administrator (or the user, etc.)enters a final adjustment position for each band—such as read from ascale arranged between the left and right junctions 110, 112 and eachband—into the native EEG test application executing on the connectedcomputing device; and the native EEG test application maps a finaladjustment position for each band to known positions of electrode arraysalong each band to select a particular electrode in each electrode arraythat best fulfills electrode position rules specified by the 10-20system.

In one example, for the second band 122 that supports an F3 electrodearray at the F3 position, an F4 electrode array at the F4 position, anda fixed Fz electrode at the Fz position, the native EEG test applicationaccesses a lookup table or electrode map defining a position of eachelectrode in each of the F3 and F4 electrode arrays relative to thefixed Fz electrode. The native EEG test application can also retrieve alookup table or parametric model (e.g., a mathematical equation) linkingadjustment positions of the second band 122 to an effective distancebetween the fixed Fz electrode and the fixed T3 (or T4) electrode. Thenative EEG test application then divides this effective distance by two,selects a particular electrode from the electrode array at the F4position that falls nearest this halved effective distance, activatesthis particular electrode in the F4 electrode array, and deactivates allother electrodes in the F4 electrode array. The native EEG testapplication can implement similar methods and techniques to activate aparticular electrode in the F3 electrode array.

Alternatively, the native EEG test application can access a lookup tableor other model that directly specifies electrodes in electrode arraysthroughout the EEG headset 100 that meet electrode position rules of the10-20 system for specific adjustment positions of each band. The nativeEEG test application can then implement similar methods and techniquesdescribed above to select specific electrodes in electrode arrays at theF7, F8, C3, C4, P3, P4, O1, and O2 positions along the first, third,fourth, and fifth bands. The native EEG test application can then push acommand to activate these select electrodes back to the EEG headset 100,which can implement these electrode specifications during the subsequentEEG test.

Yet alternately, in this implementation, the native EEG test applicationcan transmit final band adjustments—entered by the EEG testadministrator into the native EEG test application—to the EEG headset100, and a controller 184 within the EEG headset 100 can implement theforegoing methods and techniques locally to selectively activate anddeactivate electrodes within electrode arrays throughout the EEG headset100 based on these final band adjustments in order to achieve a bestapproximation of the 10-20 system (or other biosignal acquisitionsystem) during the current EEG test.

5.2 Automatic Activation

Alternatively, each band in the EEG headset 100 can include a linearpotentiometer interposed between the band 121 and the left (or right)junction, wherein the internal electrical resistance of each linearpotentiometer changes as a function of the position of the band 121,such as a function of a distance from a first end of the band 121 to theleft junction 110. The EEG headset 100 (e.g., a controller 184) can:sample linear potentiometers coupled to each band and transform voltagesread from these linear potentiometers into adjustment positions of eachband; and then transform a voltage read across each linear potentiometer(or a resistance of each potentiometer) into an adjustment position ofthe corresponding band, such as by passing the voltage read from thepotentiometer into a lookup table or mathematical model. The controller184 can then implement methods and techniques described above to selectparticular electrodes in each electrode array that best fit the 10-20system. Alternatively, the EEG headset 100 can access a lookup tablethat directly maps a voltage read across each potentiometer (or aresistance of each potentiometer) to a particular electrode in eachelectrode array on the corresponding band, as described above. The EEGheadset 100 can then activate these select electrodes and deactivate allother electrodes in the electrode arrays in the EEG headset 100 duringthe subsequent EEG test.

However, in this variation each band can include a positional sensor ofany other type, such as a mechanical, optical, or magnetic opticalencoder, as described above.

6. Replacement Electrodes Tips

In one implementation, the sense electrodes include replaceable tips.For example, each sense electrode can include a magnetic element 143adjacent or behind a terminal electrically coupled to an input of anamplifier within the sense electrode and configured to retain aremovable electrode tip containing a ferrous element 148. In thisexample, the magnetic element 143 in each sense electrode can beconfigured to retain any of: an elastic bristle electrode tip; a rigidprong electrode tip; a flat contact disk electrode tip; a domed contactdisk electrode tip; and/or any other type or geometry of electrode tip.Alternatively, each electrode can include a mechanical electrode tipretainer (e.g., a latch) configured to accept, retain, and then releasean electrode tip.

In the variation described above in which the EEG headset 100 includeselectrode arrays, each electrode array can similarly include a magneticelement 143 or other mechanical feature configured to retain a removablearray of like electrode tips 144 containing a ferrous element 148 orother mating feature. In this example, each array of electrode tips 144can include multiple discrete and electrically isolated electrode tips144 arranged in a single assembly that can be installed and then removedfrom an electrode array.

However, each electrode or electrode array in the EEG headset 100 can beconfigured to transiently receive electrode tips 144 (e.g., replacementelectrode tips) of any other type or geometry.

7. Control Module

In one variation shown in FIGS. 1 and 3, the EEG headset 100 furtherincludes a controller 184, a signal processor, a battery, and/or awireless communication module 183 arranged within a control module 180coupled to or physically coextensive with the fifth band 125 (or withthe central body described above). Generally, the control module 180 cancontain various controls, communication, and power components of the EEGheadset 100 and can be mounted to or integrated into the rearmost (e.g.,the fifth) band in order to: maintain access to various related controlsand ports; limiting obstruction to the user's vision and movements;and/or to counterbalance the EEG headset 100, thereby improvingstability of the EEG headset 100 during an EEG test.

For example, the EEG headset 100 can include: a fifth band 125 spanningthe left junction 110 and the right junction 112 and configured toextend proximal a base of a skull of a user when the EEG headset 100 isworn on the head of the user; a housing 181 arranged on the fifth band125; and a battery 182, a controller 184, and a wireless transmitter 183arranged in the housing 181, as shown in FIGS. 1 and 3. In this example,the controller 184 can be configured to read a set of analog sensesignals from active electrodes within the EEG headset 100 (e.g., thefirst electrode 140, the second electrode 152, the third electrode 153,etc.) during an EEG test performed at the EEG headset 100, such asdescribed in U.S. patent application Ser. No. 15/351,016. In thisexample, the wireless transmitter 183 can wirelessly transmit digitalrepresentations of the set of analog sense signals recorded by thecontroller 184, such as to a remote database via a local hub or wirelessrouter in real-time during the EEG test.

The EEG headset 100 can also include a set of wires passing from thecontrol module 180 (or the fifth band 125) to sense electrodes in otherbands throughout the EEG headset 100 and configured to communicate sensesignals from the sense electrodes back to the controller 184 and/orsignal processor.

However, the control module 180 can be arranged within or distributedacross the EEG headset 100 in any other form or format. Elements of thecontrol module 180 can also be integrated into the connected computingdevice (e.g., the controller 184 or processor), and sensor signals andcontrol commands can be communicated between the connected computingdevice and the EEG headset 100 via a wired or wireless connection.

8. Drive and Reference Electrodes

The EEG headset 100 can also include a reference electrode and a driveelectrode (or a “driven right leg” electrode), as described in U.S.patent application Ser. No. 15/351,016. Like each sense electrode, thedrive electrode can define a dry EEG sensor, and including: a substrate;an electrode tip extending from or (transiently) electrically coupled toa first side of the substrate; and an amplifier coupled to the substrateopposite the electrode tip and configured to amplify an electricalsignal detected by the electrode tip. In this implementation, theamplifier can output a low-impedance reference signal that follows ahigh-impedance reference signal read at the electrode tip to the signalprocessor or controller 184 described above. However, the driveelectrode can include any other type of dry- or wet-type EEG electrodeand can output any other signal to the signal processor or controller184. The drive electrode can include a fixed or interchangeableelectrode tip of a similar geometry.

In one implementation, the drive electrode is fixedly mounted to thefirst band 121 between sense electrodes in the FP1 and FP2 positions.Alternatively, the drive electrode can be mounted to a beam that pivotsor extends downwardly from the right junction 112 or from the right sideof the control module 180; the beam can be configured to locate anddepress the drive electrode onto the user's skin, such as below theuser's right ear. The reference electrode can be similarly mounted to abeam that pivots or extends downwardly from the left junction 110 orfrom the left side of the control module 180 to locate and depress thereference electrode onto the user's skin, such as below the user's leftear.

Alternatively, the EEG headset 100 can include a sixth band configuredto drop (e.g., pivot downwardly) from the fifth band 125, and the driveand reference electrodes can be mounted to the sixth band. In yetanother implementation, the drive and reference electrodes can becoupled to loose, elastic wires configured to (transiently) plug intothe control module 180 and can be configured to stick onto or to betaped onto the user's skin substantially remotely from the user's scalp.However, the drive and reference electrodes can be arranged within theEEG headset 100 in any other way.

9. Optical Detector

In one variation, the EEG headset 100 further includes an opticaldetector 190 facing outwardly from the front band (e.g., configured tolie across a user's forehead) and configured to output a signal thatfollows variations in local light intensity. In this variation, thecontroller 184 can record a first EEG signal output by a first electrode140 in the EEG headset 100 to a first sense channel and record a secondEEG signal output by a second electrode 152 in the EEG headset 100 to asecond sense channel; record a third EEG signal output by the thirdelectrode 153 in the EEG headset 100 to a third sense channel; etc., asdescribed above. The controller 184 can also record a signal output bythe optical detector 190 to a strobe channel synchronized to the firstsense channel, the second sense channel, and the third sense channel.

Therefore, in this variation, the optical detector 190 can output asignal that follows the intensity of light output by an active strobelight (or “photic stimulator”) facing a user during an EEG test; and thecontroller 184 can record the output of the optical detector 190 to astrobe channel temporally synchronized to sense channels for each senseelectrodes in the EEG headset 100. For example, during each samplingperiod (e.g., at a rate of 500 Hz) during an EEG test, the controller184 can: write digital representations of the voltage at each senseelectrode during the current sampling period to its corresponding sensechannel; read the analog output of the optical detector 190 during thecurrent sampling period; write a HI (or “i”) value to the strobe channelif the value of the analog output signal of the optical detector 190exceeds a threshold value; and write a LO (or “o”) value to the strobechannel if the value of the analog output signal of the optical detector190 is less than a threshold value. In this example, the controller 184can repeat this process for each sampling period to record synchronized,temporal representations of electrical activity at various regions ofthe user's brain and strobe light activity near the user over theduration of an EEG test.

10. Tape

In one variation, the EEG headset 100 accompanies a measurement tape. Inthis variation, the measurement tape can include: a first sidecontaining a centerline measurement scale; and a second side containinga circumferential measurement scale. During setup, an EEG testadministrator can run the measurement tape—first side facing up—from thebase of a user's skull to the user's forehead, read a value from themeasurement tape representing this centerline distance, and then setband adjusters in the second, third, and fourth bands in the EEG headset100 such that their corresponding scales read this value. The EEG testadministrator can thus adjust the second, third, and fourth bands—thatextend over the top of the user's skull—to initial positions that mayaccept the user's upper skull shape and size and that may approximatefinal adjustment settings of the EEG headset 100 for the user, as shownin FIG. 7.

The EEG test administrator can then run the measurement tape—second sidefacing out—from around the circumference of the user's skull just abovethe user's ears, read a value from the measurement tape representingthis circumferential distance, and then set band adjusters in the firstand fifth bands in the EEG headset 100 such that their correspondingscales read this value. The EEG test administrator can thus adjust thefirst and fifth bands—that wrap around the circumference of the user'sskull—to initial positions that may accept the full breadth and lengthof the user head and that may approximate final adjustment settings ofthe EEG headset 100 for the user.

Once initial adjustment positions of the first, second, third, fourth,and fifth bands of the EEG headset 100 are thus set based on values readfrom the measurement tape, the EEG test administrator can place the EEGheadset 100 onto the user's head and make final adjustments to the bandsvia the band adjusters to achieve proper contact between the senseelectrodes and the user's skin.

The systems and methods described herein can be embodied and/orimplemented at least in part as a machine configured to receive acomputer-readable medium storing computer-readable instructions. Theinstructions can be executed by computer-executable componentsintegrated with the application, applet, host, server, network, website,communication service, communication interface,hardware/firmware/software elements of a user computer or mobile device,wristband, smartphone, or any suitable combination thereof. Othersystems and methods of the embodiment can be embodied and/or implementedat least in part as a machine configured to receive a computer-readablemedium storing computer-readable instructions. The instructions can beexecuted by computer-executable components integrated bycomputer-executable components integrated with apparatuses and networksof the type described above. The computer-readable medium can be storedon any suitable computer readable media such as RAMs, ROMs, flashmemory, EEPROMs, optical devices (CD or DVD), hard drives, floppydrives, or any suitable device. The computer-executable component can bea processor but any suitable dedicated hardware device can(alternatively or additionally) execute the instructions.

As a person skilled in the art will recognize from the previous detaileddescription and from the figures and claims, modifications and changescan be made to the embodiments of the invention without departing fromthe scope of this invention as defined in the following claims.

We claim:
 1. A system for collecting biosignal data, comprising: aheadset defining a first junction and a second junction and comprising aband extending between the first junction and the second junction of theheadset; a support block comprising a distal surface: inwardly offsetfrom the band by a fixed distance; configured to rest against a head ofa user; and configured to support a portion of a weight of the headseton the head of the user; and a first electrode comprising: a firstelectrode tip comprising a first set of contact surfaces configured tocontact a scalp of the user; an electrode body configured to transientlycouple to the first electrode tip and to communicate a sense signal fromthe first electrode tip to a controller; and a spring element: coupledto the electrode body; configured to, locate the first set of contactsurfaces of the first electrode tip inwardly past the distal surface ofthe support block; and configured to, in a compressed position, displacethe first electrode toward the band responsive to contact between thefirst electrode tip and the scalp of the user.
 2. The system of claim 1,wherein the electrode body further comprises: a proximal end coupled toa first node of the headset; and a first magnetic element arranged on adistal end of the electrode body, comprising a conductive surface, andelectrically coupled to the controller.
 3. The system of claim 1,wherein the electrode body further comprises a retraction shoulderextending laterally from the electrode body between the band and thefirst electrode tip.
 4. The system of claim 1: wherein the springelement is: interposed between the band and the electrode body; andconfigured to support manual retraction of the first electrode tip pastthe distal surface of the support block toward the band to separate thefirst electrode tip from the scalp of the user.
 5. The system of claim1, further comprising a second electrode comprising a second electrodetip comprising a second set of contact surfaces distinct from the firstset of contact surfaces.
 6. The system of claim 5: wherein the first setof contact surfaces defines a first set of pronged contact elements of afirst length; and wherein the second set of contact surfaces of thesecond electrode tip defines a second set of pronged elements of asecond length greater than the first length.
 7. The system of claim 6,wherein the spring element is configured to: drive the first set ofcontact surfaces of the first electrode tip into the scalp of the userwith a first force within the range of target electrode tip forces; anddrive the second set of contact surfaces of the second electrode tipinto the scalp of the user with a second force approximating the firstforce.
 8. A biosignal headset system comprising: a band extendingbetween a first junction and a second junction on the headset; a supportblock arranged on the band and comprising a distal surface configured tosupport a portion of a weight of the headset on a head of a user; afirst electrode arranged adjacent the support block and comprising afirst electrode tip and an electrode body; and a spring element: coupledto the electrode body; configured to, in a resting position, locate afirst set of contact surfaces of the first electrode tip inwardly pastthe distal surface of the support block; and configured to, in acompressed position, displace the first electrode toward the bandresponsive to contact between the first electrode tip and a scalp of theuser.
 9. The system of claim 8, wherein the first electrode tipcomprises a first set of contact surfaces configured to contact thescalp of the user.
 10. The system of claim 9, wherein the electrode bodyis further configured to transiently couple to the first electrode tipand to communicate a sense signal from the first electrode tip to acontroller.
 11. The system of claim 10, wherein the electrode bodyfurther comprises: a proximal end coupled to a first node of theheadset; and a first magnetic element arranged on a distal end of theelectrode body, comprising a conductive surface, and electricallycoupled to the controller.
 12. The system of claim 9, further comprisinga second electrode comprising a second electrode tip comprising a secondset of contact surfaces configured to contact the scalp of the user. 13.The system of claim 12: wherein the first set of contact surfacesdefines a first set of pronged contact elements of a first length; andwherein the second set of contact surfaces of the second electrode tipdefines a second set of pronged elements of a second length greater thanthe first length.
 14. The system of claim 13, wherein the spring elementis configured to: drive the first set of contact surfaces of the firstelectrode tip into the scalp of the user with a first force within therange of target electrode tip forces; and drive the second set ofcontact surfaces of the second electrode tip into the scalp of the userwith a second force approximating the first force.
 15. The system ofclaim 12, wherein the electrode body is further configured totransiently couple to the second electrode tip and to communicate asense signal from the second electrode tip to a controller.
 16. Thesystem of claim 15, wherein the controller is configured to transientlyconnect to the first electrode tip or the second electrode tip.
 17. Thesystem of claim 12: wherein the first set of contact surfaces of thefirst electrode tip defines a first contact area configured to contactthe scalp of the user; wherein the second set of contact surfaces of thesecond electrode tip defines a second contact area configured to contactthe scalp of the user; and wherein the support block defines a thirdcontact area, greater than the first contact area and the second contactarea, configured to contact the scalp of the user.
 18. A biosignal datacollection system comprising: an electrode body arranged on a headsetband and comprising a first magnetic element arranged on a distal end ofthe electrode body and comprising a conductive surface; a kit ofelectrode tips, each electrode tip in the kit of electrode tipscomprising a secondary magnetic element configured to transiently couplethe electrode tip to the first magnetic element; a support blockarranged on the headset band and configured to support a weight of aheadset on a scalp of a user; and a spring element: coupled to theelectrode body; configured to, in a resting position, locate theelectrode tip inwardly past a distal surface of the support block; andconfigured to, in a compressed position, displace the electrode towardthe headset band responsive to contact between the electrode tip and thescalp of the user.
 19. The system of claim 18, wherein the kit ofelectrode tips comprises: a first electrode tip comprising a firstcontact surface in a first configuration; and a second electrode tipcomprising a second contact surface in a second configuration distinctfrom the first configuration.
 20. The system of claim 19, wherein thespring element is configured to: drive the first contact surface of thefirst electrode tip into the scalp of the user with a first force withinthe range of target electrode tip forces; and drive the second contactsurface of the second electrode tip into the scalp of the user with asecond force approximating the first force.